LG Heat Pump Dryers: 'AE' Error Diagnosis

⚠️ SAFETY WARNING / ELECTRICAL HAZARD. Before any checks, it is essential to disconnect the dryer from the electrical supply using the main circuit breaker or by unplugging it from the wall socket. As this is a 230V appliance, there is a serious risk of electric shock. Any intervention on internal components must be performed exclusively by a qualified technician. ReeFix provides this diagnosis for informational purposes only.

REAL CASE

A user reported that their LG heat pump dryer regularly displays the 'AE' error code approximately 10-15 minutes after the cycle starts. They noticed that the compressor, before stopping, emits a slightly abnormal hum, and the rear area of the appliance, where the compressor is located, feels excessively hot to the touch. After turning the dryer off and on again, the error temporarily disappears, allowing the device to restart, but it consistently reappears during the next cycle or even after a few minutes. This intermittent behavior is a key indicator of a problem that manifests under thermal or electrical load.

GENERAL PATTERN

The 'AE' error on LG dryers with Dual Inverter heat pumps indicates a critical anomaly in the heat generation system, specifically related to the compressor or its power supply/cooling. The main electronic board (Main PCB) detects abnormal compressor operation, such as a blockage, out-of-spec current draw, or overheating.

Causes and Probabilities:

1. Inverter electronic board (IPM) failure - 45%

   • Why: This module drives the compressor. If the filter capacitors lose capacity or the IPM module itself experiences an internal short circuit, the compressor does not receive the correct power, causing it to seize.
   • Key signals: The compressor attempts to start with a weak or abnormal hum and then stops immediately. The board may show swollen capacitors or signs of overheating/burns.
   • Often happens when: The appliance is several years old or has been subjected to frequent intensive work cycles.

2. Cooling fan (BLDC) malfunction or blockage - 30%

   • Why: This fan cools the compressor. If blocked or faulty, the compressor overheats rapidly, activating the thermal protector (OLP) which shuts it down for safety. The main board interprets this shutdown as an anomaly.
   • Key signals: The error appears after 10-15 minutes of operation, with the compressor being extremely hot.
   • Typical user error: Failure to clean external ventilation grilles or internal filters, which can reduce overall airflow and overload the cooling system.

3. Mechanical blockage or internal compressor failure - 15%

   • Why: A blockage of the rotary piston or a refrigerant gas leak can cause the compressor to overheat and mechanically seize.
   • Key signals: Loud metallic noise at startup, followed by a current draw spike. Internal electrical windings may be unbalanced or short-circuited.

4. Faulty wiring or inaccurate temperature sensors (NTC) - 10%

   • Why: A broken wire or an NTC sensor providing incorrect readings can cause the board to misinterpret operating conditions or not receive the signal from the compressor.
   • Key signals: The error appears immediately when the dryer is turned on, even before the compressor attempts to start.

WHAT TO DO NOW

To decide whether to repair yourself, call a technician, or replace, follow this quick assessment:

1. Repair yourself (Safe Preliminary Checks):

   • Action: The only action a user can safely take is a very thorough cleaning.
     • Unplug the dryer from the power.
     • Thoroughly clean all filters (door filter, lower heat exchanger filter).
     • Check for any obvious obstructions in the external ventilation grilles of the appliance, especially at the back or bottom where the compressor is located.
     • If possible, use a compressed air duster to remove lint from accessible areas without disassembly.
   • Cost: Low (your own time).
   • Probability of resolution: Low (about 5-10%), but it is a fundamental step to rule out minor obstructions that could overload the system. If the error persists after thorough cleaning, the problem is internal.

2. Contact a Specialized Technician (Recommended for 90% of cases):

   • Reason: Given the complexity of the heat pump circuit and the presence of high voltages, any internal intervention requires specific skills and tools.
   • What to expect from the technician (Output for technician):
     • The technician will first check the integrity of the LG inverter electronic board (IPM). This is the most likely failure (45%). The replacement cost for the inverter board is around 150-300 euros (part + labor).
     • Next, they will check the LG BLDC fan motor for compressor cooling (30% probability). A blockage or failure of this fan is a common cause. The replacement cost is usually between 80-180 euros (part + labor).
     • They will assess the integrity of the compressor itself and the LG NTC temperature sensor (15% for compressor, 10% for sensors/wiring).
   • Repair costs (indicative estimates):
     • Inverter Board Replacement: Medium-high cost (150-300 euros).
     • BLDC Fan Motor Replacement: Medium cost (80-180 euros).
     • Sensor Replacement/Wiring Repair: Low-medium cost (50-120 euros).
     • Compressor Replacement: Very high cost (300-600+ euros, often uneconomical).

3. Replace the Device:

   • When: If the technician's diagnosis indicates a compressor failure (the most expensive component) or if the dryer is old and the estimated repair cost (even for IPM or fan) exceeds 50% of the value of a new equivalent appliance. In these cases, replacement offers a more durable and guaranteed solution.

Operational Decision: If the 'AE' error persists after thorough external cleaning, contact a specialized technician for an internal diagnosis; if the fault turns out to be the compressor or the inverter board on an old appliance, consider replacing the dryer.